1. Field of the Invention
This invention relates to method and apparatus for attaching sheet material, and more particularly roofing sheet material, to a base, or roof, and the product thereof.
2. Description of the Prior Art
Sheet roofing materials, such as asphalt treated paper, felt, and the like, have long been in use as a covering for a bare roof surface, prior to the application to the roof surface of a weather proofing material, such as asphalt. Sheet materials are conventionally laid out upon a roof in strips so as to overlap at their edges. In order to hold the sheets to the roof, it is necessary to attach the sheets together at the overlapping edges and, in addition, where the sheets are of a substantial width, to attach the individual sheets themselves to the roof between adjacent edge attachments. While a variety of systems have been utilized for making this attachment, the system generally used at present is to place a thin metal disc at the point of attachment, and drive a nail through the disc into the roof surface. The disc provides an extended head area for the nail, so as to inhibit the sheet material from being pulled away from the nail itself. Because of the tearing characteristics of the sheet material, rips often occur between adjacent points of attachment, either during working upon the roof prior to the weather proofing material application, or by reason of wind and the like. Furthermore, manual nailing of the discs to the sheet material is laborious, time consuming and expensive.